The Bigger Picture: Why Oral Mucosa Heals Better Than Skin

Challenges and improvements in multi-layer mucosa-adhesive films for oral diseases treatment and prognosis

Due to the complexity of oral physiology and pathology, the treatment of oral diseases faces multiple and complex clinical requirements. Mucosa-adhesive films (MAFs) with a single layer have demonstrated considerable potential in delivering therapeutic bioactive ingredients directly to the site of oral diseases. However, their functions are often hindered by certain factors such as limited loading capacity, poor site specificity, and sensitivity to mechanical stimuli. To overcome these limitations, the development of multi-layer MAFs has become a focal point for recent research. This involves the improvement of construction methods for multi-layer MAFs to minimize potential health risks from residual solvents, and conducting comprehensive in vivo studies to evaluate their safety and therapeutic efficacy more accurately, thus paving the way for their commercialization. Additionally, the exploration of multi-layer MAFs as personalized drug delivery systems could further broaden their application prospect. Precisely, multi-layer MAFs compensate for the shortcomings of current therapeutic strategies for oral diseases to a great extent, indicating a promising future in the market.

Enhancing linezolid activity in the treatment of oral biofilms using novel chitosan microneedles with iontophoretic control

This study aimed to prepare and assess active microneedle (MN) patches based on a novel biomaterial and their effective coupled (physical and electrical) transdermal delivery of a model drug (Linezoid). Modified MN patches (e.g. fabricated from Linezoid, boronated chitosan, polyvinyl alcohol and D-sorbitol) were engineered using a vacuum micromoulding method. Physicochemical, FTIR (Fourier transform infrared), in-silico, structural and thermal analysis of prepared formulations were conducted to ascertain MN quality, composition and integrity. In-vitro mechanical tests, membrane toxicity, drug release, antibiofilm, ex-vivo mucoadhesion, insertion and in-vivo antibiofilm studies were performed to further validate viability of the coupled system. Optimized MN patch formulation (CSHP3 - comprising of 3 % w/v boronated chitosan, 3.5 % w/v PVA and 10 % w/w D-sorbitol) exhibited sharp-tipped, equi-distant and uniform-surfaced micron-scaled projections with conforming physicochemical features. FTIR analysis confirmed modification (i.e., boronation) of chitosan and compatibility as well as interaction between CSHP3 constituents. In-silico analysis indicated non-covalent interactions between all formulation constituents. Moreover, boronated chitosan-mucin glycoprotein complex showed a stronger bonding (∼1.86 times higher CScore) as compared to linezolid-mucin counterpart. Thermal analysis indicated amorphous nature of CSHP3. A ∼ 1.42 times higher tensile strength was displayed by CSHP3 as compared to control (i.e., pure chitosan, polyvinyl alcohol and D-sorbitol-based MN patch). Membrane toxicity study indicated non-toxic and physiological compatible nature of CSHP3. Within 90 min, 91.99 ± 2.3 % linezolid was released from CSHP3. During release study on agarose gel, CSHP3-iontophoresis treatment resulted in a ∼ 1.78 and ∼ 1.20 times higher methylene blue-covered area and optical density, respectively, within 60 min as compared to CSHP3 treatment alone. Staphylococcus aureus biofilms treated with CSHP3 exhibited 65 ± 4.2 % reduction in their mass. CSHP3 MN patches remained adhered to the rabbit oral mucosa for 6 ± 0.15 h. Mucosa treated with CSHP3 and CSHP3-iontophoresis combination showed a generation of pathways in the epithelium layers without any damage to the underlying lamina propria. Eradication of Staphylococcus aureus from oral mucosal wounds and complete tissue regeneration was recorded following 7-day treatment using CSHP3-iontophoresis coupled approach.

Histopathological Evaluation of Wound Healing and Anti-Inflammatory Effects of Granola Potato Peel Ethanol Extract in Rat Oral Mucosa

Introduction

Oral mucosal wounds present significant clinical challenges due to their susceptibility to infection, inflammation, and delayed healing. The limitation of standard anti-inflammatory drugs (both steroidal and non-steroidal) highlights the urgent need for plant-derived alternative therapies. Granola potato (Solanum tuberosum L.) from Pangalengan, West Java, Indonesia, has shown promise due to its bioactive compounds. However, its potential for wound healing and anti-inflammatory effects, specifically for oral mucosal wounds, remains largely unexplored.

Purpose

To evaluate the wound healing and anti-inflammatory activity of Granola potato peel ethanol extract (GPPEE) on the oral mucosa of Wistar rats based on histopathological analysis.

Materials and Methods

Forty-eight Wistar rats were wounded on the palatal mucosa using a 4 mm punch biopsy and subsequently divided into four groups: placebo gel, 0.1% triamcinolone acetonide ointment (TCA), 4% GPPEE gel, and 6% GPPEE gel. The rats were euthanized on days 0, 1, 3, 7, and 14. Histopathological parameters assessed included fibroblast proliferation, collagen deposition, angiogenesis, and the presence of inflammatory cells.

Results

Phytochemical screening revealed the presence of phenolic compounds, flavonoids, tannins, and alkaloids in the Granola potato peel ethanol extract (GPPEE). Significant differences in the number of inflammatory cells were observed on days 1, 3, 7, and 14 (p<0.05), with the groups treated with 4% and 6% GPPEE gel initially exhibiting pro-inflammatory effects on day 3, followed by significant anti-inflammatory effects on days 7 and 14. The 6% GPPEE gel treatment demonstrated a notable increase in fibroblasts on days 1, 7, and 14 (p<0.05), as well as collagen deposition on days 7 and 14 (p<0.05). However, no significant difference was observed in angiogenesis (p>0.05).

Conclusion

The application of 4% and 6% GPPEE gel demonstrated superior wound healing efficacy compared to 0.1% TCA and exhibited comparable anti-inflammatory activity to 0.1% TCA.

Streptococcus mitis enhances metal-induced apoptosis in reconstructed human gingiva but not skin

BACKGROUND

Commensal bacteria colonizing oral mucosa and skin play an essential role in maintaining host-microbiome homeostasis. It is unknown whether cytotoxicity resulting from metal ions leaching from medical devices may be influenced by commensal microbes.

OBJECTIVE

Determine whether the extent of apoptosis triggered by nickel or titanium ions is influenced by Streptococcus mitis and whether apoptosis occurs via the intrinsic or extrinsic apoptosis pathway.

METHODS

Reconstructed Human Gingiva (RHG) and Skin (RHS) were topically exposed to titanium or nickel salts in the presence or absence of S. mitis. Cytotoxicity and apoptosis were assessed by histology, immunohistochemistry, TUNEL assay, and Western Blot.

RESULTS

S. mitis alone resulted in negligible cytotoxicity. After metal exposure, localized apoptosis was observed in the epithelium and fibroblasts within the lamina propria hydrogel of both RHG and RHS. S. mitis enhanced metal-mediated apoptosis in gingiva but not in skin. Apoptosis was mediated via the extrinsic pathway caspase 8. Activation of the execution phase of apoptosis occurred via caspases 3 and 7, and PARP-1.

CONCLUSION

Our study supports the finding that metals have irritant, cytotoxic properties resulting in apoptosis when leaching into skin or gingiva. Particularly for gingiva, commensal microbes exaggerate this detrimental effect.

Naltrexone accelerated oral traumatic ulcer healing and downregulated TLR-4/NF-kB pathway in Wistar rats

OBJECTIVE

To assess the effect of naltrexone on oral mucosal healing using a traumatic ulcer model DESIGN: Wistar rats (n = 112) received distilled water (control) or naltrexone (0.5, 10, or 50 mg/kg/day). Ulcers were induced on the buccal mucosa using a round skin biopsy punch (diameter 6 mm). Euthanasia was performed on days 1, 3, 7, and 14. Healing was assessed by ulcer area, histological scores, histomorphometric analysis (number of polymorphonuclears, mononuclears, and fibroblasts), and collagen percentage. Immunohistochemistry for TLR-2, TLR-4, NF-kB, and CD31 was evaluated. Nociceptive threshold was measured daily.

RESULTS

The 50 mg/kg group showed reduced ulcer area on days 1 (p < 0.001), 3 (p < 0.05), and 14 (p < 0.01). In this group, there was, on day 14, an increase in the percentage of reepithelization (p = 0.043) and collagen (p < 0.05), an increase in connective tissue maturation (p = 0.016), and on day 7 an increase in fibroblasts (p < 0.001). The 10 mg/kg dose reduced the ulcer area on day 1 (p < 0.001). The 50 mg/kg group showed lower expression of TLR-4 (p < 0.001) on day 1, NF-kB on days 1 (p < 0.05) and 14 (p < 0.05), and CD31 on day 14 (p < 0.05). The 0.5 and 10 mg/kg doses reduced TLR-4 expression on day 1 (p < 0.05; p < 0.01, respectively). Nociceptive threshold increased in the 50 mg/kg group (p < 0.01).

CONCLUSION

Naltrexone enhanced traumatic oral ulcer healing by reducing TLR-4/NF-kB signaling and promoting fibroblast proliferation and collagen deposition. Additionally, naltrexone reduced pain in rats.

Reflecting the human lip in vitro: Cleft lip skin and mucosa keratinocytes keep their identities

OBJECTIVES

Cell models have shown great promise as tools for research, potentially providing intriguing alternatives to animal models. However, the original tissue characteristics must be maintained in culture, a fact that is often assumed, but seldom assessed. We aimed to follow the retention of the original tissue identities of cleft lip-derived skin and mucosa keratinocytes in vitro.

METHODS

Cleft lip-derived keratinocytes were isolated from discarded tissue along the cleft margins during cheiloplasty. Cell identities were assessed by immunohistochemistry and quantitative real-time PCR for tissue-specific markers and compared with native lip tissue. Moreover, keratinocytes were regularly analyzed for the retention of the original tissue characteristics by the aforementioned methods as well as by differentiation assays.

RESULTS

The various anatomical zones of the human lip could be distinguished using a panel of differentiation and functional-based markers. Using these markers, retention of the original tissue identities could be followed and confirmed in the corresponding primary keratinocytes in culture.

CONCLUSIONS

Our findings promote patient-derived cells retaining their original identities as astonishing and clinically relevant in vitro tools. Such cells allow a better molecular understanding of various lip-associated pathologies as well as their modeling in vitro, including but not restricted to orofacial clefts.

Loss of the ability to regenerate body appendages in vertebrates: from side effects of evolutionary innovations to gene loss

The ability to regenerate large body appendages is an ancestral trait of vertebrates, which varies across different animal groups. While anamniotes (fish and amphibians) commonly possess this ability, it is notably restricted in amniotes (reptiles, birds, and mammals). In this review, we explore the factors contributing to the loss of regenerative capabilities in amniotes. First, we analyse the potential negative impacts on appendage regeneration caused by four evolutionary innovations: advanced immunity, skin keratinization, whole-body endothermy, and increased body size. These innovations emerged as amniotes transitioned to terrestrial habitats and were correlated with a decline in regeneration capability. Second, we examine the role played by the loss of regeneration-related enhancers and genes initiated by these innovations in the fixation of an inability to regenerate body appendages at the genomic level. We propose that following the cessation of regenerative capacity, the loss of highly specific regeneration enhancers could represent an evolutionarily neutral event. Consequently, the loss of such enhancers might promptly follow the suppression of regeneration as a side effect of evolutionary innovations. By contrast, the loss of regeneration-related genes, due to their pleiotropic functions, would only take place if such loss was accompanied by additional evolutionary innovations that compensated for the loss of pleiotropic functions unrelated to regeneration, which would remain even after participation of these genes in regeneration was lost. Through a review of the literature, we provide evidence that, in many cases, the loss in amniotes of genes associated with body appendage regeneration in anamniotes was significantly delayed relative to the time when regenerative capability was lost. We hypothesise that this delay may be attributed to the necessity for evolutionary restructuring of developmental mechanisms to create conditions where the loss of these genes was a beneficial innovation for the organism. Experimental investigation of the downregulation of genes involved in the regeneration of body appendages in anamniotes but absent in amniotes offers a promising avenue to uncover evolutionary innovations that emerged from the loss of these genes. We propose that the vast majority of regeneration-related genes lost in amniotes (about 150 in humans) may be involved in regulating the early stages of limb and tail regeneration in anamniotes. Disruption of this stage, rather than the late stage, may not interfere with the mechanisms of limb and tail bud development during embryogenesis, as these mechanisms share similarities with those operating in the late stage of regeneration. Consequently, the most promising approach to restoring regeneration in humans may involve creating analogs of embryonic limb buds using stem cell-based tissue-engineering methods, followed by their transfer to the amputation stump. Due to the loss of many genes required specifically during the early stage of regeneration, this approach may be more effective than attempting to induce both early and late stages of regeneration directly in the stump itself.

Enhancing early-stage healing responses through the modified "Poncho" technique in customized titanium mesh-mediated bone regeneration: A soft tissue management approach-case series

RATIONALE

Soft tissue management is critical in bone augmentation surgery to prevent wound dehiscence. Several strategies for passive tissue primary closure have been explored. This article introduces a flap design known as the modified "Poncho" technique (MPT), integrated with customized titanium mesh-mediated bone regeneration, and investigates the healing quality during the initial stages of an incision.

PATIENT CONCERNS

The cohort consisted of 5 patients undergoing customized bone regeneration procedures, concerned primarily with the successful integration and healing of the augmented bone site without complications such as wound dehiscence or infection.

DIAGNOSIS

All patients were diagnosed with insufficient bone volume requiring augmentation to support future dental implants, necessitating the use of customized titanium mesh for guided bone regeneration.

INTERVENTIONS

The MPT was detailed and applied during the customized bone regeneration procedures. Postoperative evaluations included recording complications and using Landry's healing index at intervals of 3, 7, 14, and 30 days post-surgery to assess the technique's performance in early wound closure.

OUTCOMES

The study found that 95.7% of surgery sites experienced uneventful soft tissue healing within the observation period. Only 1 of 23 sites exhibited partial wound dehiscence at postsurgical days 14 and 30, accompanied by mild inflammation. The Landry's healing index increased from 3 ± 0.47 to a final value of 4.69 ± 1.06, indicating substantial improvement in healing over time.

LESSONS

The MPT shows promise as an innovative approach for promoting passive and predictable primary wound closure beneath a digitally customized titanium mesh for bone regeneration, demonstrating a high rate of successful healing and minimal complications during the early postoperative phase.

Human salivary histatin 1 regulating IP3R1/GRP75/VDAC1 mediated mitochondrial-associated endoplasmic reticulum membranes (MAMs) inhibits cell senescence for diabetic wound repair

RATIONALE

Difficulty in skin wound healing is a concern for diabetic patients across the world. Impaired mitochondrial dysfunction and aging-related vascular dysfunction in human umbilical vein endothelial cells (HUVECs) caused by oxidative stress are major impediments to diabetic wound healing. However, research on skin repair at the mechanistic level by improving mitochondrial function and inhibiting oxidative stress-induced HUVEC senescence remains lacking.

METHODS AND RESULTS

Human saliva effectively inhibits the natural aging of HUVECs through immunodepletion experiments. Histatin 1 (Hst1), a short peptide comprising 38 amino acids, is the primary component of human saliva that prevents HUVEC aging. Based on in vitro findings, Hst1 decreased staining for senescence-associated β-galactosidase activity and expression of mediators of senescence signaling, including p53, p21, and p16. Mechanistically, HUVEC senescence is associated with Hst1-modulated nuclear factor Nrf2 signaling as Hst1 induces ERK-mediated Nrf2 nuclear translocation through NADPH oxidase-dependent ROS regulation, reinforced Nrf2 antioxidant response, and suppressed oxidative stress. RNA sequencing identified that the mitochondrial-related gene set was enriched in the Hst1 group. Coimmunoprecipitation indicated that Hst1 delayed hydrogen peroxide-induced HUVEC senescence by inhibiting mitochondria-associated endoplasmic reticulum (ER) membrane formation mediated by inositol 1,4,5-trisphosphate receptor 1-glucose-regulated protein 75-voltage-dependent anion channel 1 (VDAC1) complex interactions. Furthermore, in aging HUVECs, Hst1 treatment or VDAC1 silencing with small interfering RNA hindered calcium (Ca2+) transfer from the ER to the mitochondria, thereby ameliorating mitochondrial Ca2+ overload and restoring mitochondrial function. In an in vivo mouse model of diabetes mellitus skin defects, Hst1 facilitated wound healing by stimulating the new blood vessel formation and impeding the expression of senescent biomarkers.

CONCLUSIONS

This study proposes a theoretical solution that Hst1 can restore mitochondrial function by inhibiting oxidative stress or cellular senescence, thereby promoting angiogenesis and diabetic wound repair.

SPRR1B+ keratinocytes prime oral mucosa for rapid wound healing via STAT3 activation

Oral mucosal wounds exhibit accelerated healing with reduced scarring compared to cutaneous wounds, representing an optimal wound healing paradigm. However, the specific cellular subtypes orchestrating the efficient healing of mucosal tissues remain elusive. Through a comprehensive analysis integrating bulk-mRNA and single-cell sequencing data during the wound healing process in oral mucosa and skin, we have delineated a distinct set of genes markedly upregulated during tissue repair. This collection of wound healing-associated genesets was highly enriched in a specific keratinocyte subpopulation identified as STAT3-activated SPRR1B+ keratinocytes. Notably, despite the inherent rapidity of oral mucosal healing, the induction of SPRR1B+ keratinocytes is evident in both skin and mucosal wound healing processes in murine model. Intriguingly, these wound healing-promoting SPRR1B+ keratinocytes, which are induced via STAT3 activation, inherently abundant in unwounded normal mucosa but absent in normal skin. SPRR1B knockdown significantly inhibits mucosal keratinocyte migration, a critical attribute for effective wound healing. In summary, through analysis of human oral and skin wound healing processes at single-cell resolution, coupled with validation in murine model, suggests STAT3-activated SPRR1B+ keratinocytes are associated with the rapid mucosal repair process. This discovery underscores the potential application of SPRR1B+ keratinocytes in the therapeutic management of chronic or non-healing wounds.

Small Extracellular Vesicles and Oral Mucosa: The Power Couple in Regenerative Therapies?

Although ongoing debates persist over the scope of phenomena classified as regenerative processes, the most up-to-date definition of regeneration is the replacement or restoration of damaged or missing cells, tissues, organs, or body parts to full functionality. Despite extensive research on this topic, new methods in regenerative medicine are continually sought, and existing ones are being improved. Small extracellular vesicles (sEVs) have gained attention for their regenerative potential, as evidenced by existing studies conducted by independent research groups. Of particular interest are sEVs derived from the oral mucosa, a tissue renowned for its rapid regeneration and minimal scarring. While the individual regenerative potential of both sEVs and the oral mucosa is somewhat understood, the combined potential of sEVs derived from the oral mucosa has not been sufficiently explored and highlighted in the existing literature. Serving as a broad compendium, it aims to provide scientists with essential and detailed information on this subject, including the nature of the materials employed, isolation and analysis methodologies, and clinical applications. The content of this survey aims to facilitate the comparison of diverse methods for working with sEVs derived from the oral mucosa, aiding in the planning of research endeavors and identifying potential research gaps.

Oral Patch/Film for Drug Delivery-Current Status and Future Prospects

In recent years, there has been extensive research into drug delivery systems aimed at enhancing drug utilization while minimizing drug toxicities. Among these systems, oral patches/films have garnered significant attention due to their convenience, noninvasive administration, ability to bypass hepatic first-pass metabolism, thereby enhancing drug bioavailability, and their potential to ensure good compliance, particularly among special patient populations. In this review, from the perspective of the anatomical characteristics of the oral cavity and the advantages and difficulties of oral drug delivery, we illustrate the design ideas, manufacturing techniques, research methodologies, and the essential attributes of an ideal oral patch/film. Furthermore, the applications of oral patches/films in both localized and systemic drug delivery were discussed. Finally, we offer insights into the future prospects of the oral patch/film, aiming to provide valuable reference for the advancement of oral localized drug delivery systems.

Vocal Fold Injury Produces Similar Biomechanical Outcomes in Male and Female Rabbits

OBJECTIVE

Sex differences in response to trauma and physiologic stressors have been identified in numerous organ systems but have not yet been defined in the larynx. The objective of this study was to develop an endoscopic vocal fold injury model in rabbits and to compare structural and functional outcomes between male and female subjects.

STUDY DESIGN

Basic science study.

METHODS

Two male and two female rabbits underwent unilateral endoscopic cordectomy. Animals were intubated with a size 3-0 neonatal endotracheal tube, and laryngoscopy was performed with a 4 mm Hopkins rod telescope. While visualizing, a 2 mm cupped forceps grasped and resected the mid-membranous portion of the right true vocal fold. Larynges were then harvested after 8weeks. Excised larynx phonation with high-speed videography and kymography was used to assess vibrational quality. Tissue elastic (Young's) modulus was measured by indentation.

RESULTS

Injured larynges phonated with fundamental frequencies between 237-415 Hz. In both males and females, the scarred vocal fold exhibited an increased Young's modulus compared to the contralateral nonoperated vocal fold. There were no notable differences in glottal closure pattern or vocal fold oscillation symmetry between sexes.

CONCLUSION

We have demonstrated a model for vocal fold scarring in rabbits. Vibrational and structural outcomes were similar between the examined male and female larynges.

Ulcerative colitis: the healing power of macrophages

Ulcerative colitis (UC) is a chronic and debilitating disorder that falls under the broad category of inflammatory bowel disease (IBD). Therefore, affects the colon and rectum, resulting in inflammation and ulcers in the lining of these organs. Over the years, there has been a significant shift in the management of UC. The focus has moved from achieving symptom-free daily living to attaining mucosal healing. Mucosal healing means completely restoring the colon and rectum's lining, significantly reducing the risk of complications and relapse. Macrophages are a crucial component of the immune system that play a vital role in the regeneration and repair of colonic ulcers. These immune cells are responsible for production of a variety of cytokines and growth factors that facilitate tissue repair. Macrophages are responsible for maintaining a balance between inflammation and healing. When this balance is disrupted, it can lead to chronic inflammation and tissue damage, exacerbating UC symptoms. Thus, this review aims to investigate the contribution of macrophages to mucosal repair and remission maintenance in UC patients.

Antimicrobial Activity of Antibacterial Sutures in Oral Surgery: A Scoping Review

OBJECTIVE

The aim of this scoping review was to explore and synthesise the current evidence on the antimicrobial activity of antibacterial suture materials used in oral surgery.

METHODS

The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews. A bibliographic search was carried out in the PubMed and Scopus databases to retrieve all human clinical studies that investigated the antimicrobial efficacy of antibacterial-coated sutures used in oral surgery. Included studies were screened and extracted independently by 2 examiners. Data were tabulated and qualitatively described.

RESULTS

The search initially returned 150 articles and resulted in 5 included studies after the duplicates' removal and the full-text screening. Selected studies were published from 2014 to 2019. Three studies (60%) were randomised clinical trials, whilst the remaining studies did not report information on randomisation. The antimicrobial agents for coated sutures included triclosan and chlorhexidine. In almost all the studies, antibacterial-coated sutures exhibited lower bacterial retention compared to those without coating.

CONCLUSIONS

Within limitations, the antimicrobial-coated sutures employed in oral surgery exhibited good results in terms of their microbicidal activity when compared with sutures that were not coated. Considering the high variability and confounding factors identified in the included studies, more high-quality research is needed to confirm these results. Antimicrobial-coated sutures could represent a promising and clinically valid strategy to reduce microbial colonisation in oral surgery. The reduced bacterial adherence is likely to improve the clinical success of the surgical procedures. Yet, the cost-benefit ratio of antimicrobial-coated sutures should be assessed in larger clinical trials to confirm their efficacy over conventional noncoated sutures.

Diet Outcome in Patients With Hypopharyngeal Defects Repaired With Different Reconstruction Flaps: A Comparative Study

OBJECTIVES

To assess potential risk factors influencing diet outcomes after reconstruction of subtotal hypopharyngeal defects using free patch- or tube-shaped anterolateral thigh (ALT) fasciocutaneous flaps.

STUDY DESIGN

Retrospective cohort study.

SETTING

First-level referral hospital.

METHODS

Between January 2011 and December 2020, we studied hypopharyngeal cancer patients who underwent the reconstruction of hypopharyngeal defects using free patch- or tube-shaped ALT fasciocutaneous flaps. The choice between patch- or tube-shaped ALT flaps depended on the defect's nature, favoring patch-shaped for subtotal defects and tube-shaped for circumferential defects. A restricted diet was characterized by a history of enterostomy or endoscopic esophageal dilation treatment postreconstruction. We analyzed patients with restricted diets at 1- and 3-year follow-up visits.

RESULTS

Ninety-eight patients were enrolled; 39 patch-shaped flaps, and 59 tube-shaped flaps. No significances were noted in demographics, postoperative radiotherapy (RT) or chemotherapy, rates of free flap reoperation/salvage, or complications. However, a significant difference emerged in diet outcomes at the 1-year follow-up (P = .005). The rate of a restricted diet was 6.08 times higher in patients with tube-shaped flaps compared to patch-shaped flaps (95% confidence interval [CI]: 1.95-18.94). Stratifying based on postoperative RT revealed a 5.47 times higher rate of a restricted diet in tube-shaped flap recipients compared to patch-shaped flap recipients (95% CI: 1.44-20.48). No significances were observed in 5-year survival rates.

CONCLUSION

Concerning postoperative RT, patch-shaped flaps exhibited a lower incidence of a restricted diet compared to tube-shaped flaps. Preservation of the posterior mucosa may play a crucial role in preventing RT-induced esophageal stricture.

Pilot Evaluation of Silicone Surrogates for Oral Mucosa Simulation in Craniofacial Surgical Training

Surgical simulators are crucial in early craniofacial and plastic surgical training, necessitating synthetic materials that accurately replicate tissue properties. Recent critiques of our lab's currently deployed silicone surrogate have highlighted numerous areas for improvement. To further refine our models, our group's objective is to find a composition of materials that is closest in fidelity to native oral mucosa during surgical rehearsal by expert craniofacial surgeons. Fifteen platinum silicone-based surrogate samples were constructed with variable hardness and slacker percentages. These samples underwent evaluation of tactile sensation, hardness, needle puncture, cut resistance, suture retention, defect repair, and tensile elasticity. Expert craniofacial surgeon evaluators provided focused qualitative feedback on selected top-performing samples for further assessment and statistical comparisons. An evaluation revealed surrogate characteristics that were satisfactory and exhibited good performance. Sample 977 exhibited the highest performance, and comparison with the original surrogate (sample 810) demonstrated significant improvements in critical areas, emphasizing the efficacy of the refined composition. The study identified a silicone composition that directly addresses the feedback received by our team's original silicone surrogate. The study underscores the delicate balance between biofidelity and practicality in surgical simulation. The need for ongoing refinement in surrogate materials is evident to optimize training experiences for early surgical learners.

Biofabrication Strategies for Oral Soft Tissue Regeneration

Gingival recession, a prevalent condition affecting the gum tissues, is characterized by the exposure of tooth root surfaces due to the displacement of the gingival margin. This review explores conventional treatments, highlighting their limitations and the quest for innovative alternatives. Importantly, it emphasizes the critical considerations in gingival tissue engineering leveraging on cells, biomaterials, and signaling factors. Successful tissue-engineered gingival constructs hinge on strategic choices such as cell sources, scaffold design, mechanical properties, and growth factor delivery. Unveiling advancements in recent biofabrication technologies like 3D bioprinting, electrospinning, and microfluidic organ-on-chip systems, this review elucidates their precise control over cell arrangement, biomaterials, and signaling cues. These technologies empower the recapitulation of microphysiological features, enabling the development of gingival constructs that closely emulate the anatomical, physiological, and functional characteristics of native gingival tissues. The review explores diverse engineering strategies aiming at the biofabrication of realistic tissue-engineered gingival grafts. Further, the parallels between the skin and gingival tissues are highlighted, exploring the potential transfer of biofabrication approaches from skin tissue regeneration to gingival tissue engineering. To conclude, the exploration of innovative biofabrication technologies for gingival tissues and inspiration drawn from skin tissue engineering look forward to a transformative era in regenerative dentistry with improved clinical outcomes.

Histogical changes in oral mucosa (gingiva) as a method for estimating post-mortem interval: A literature review

Estimating the post-mortem interval (PMI) is an essential step in forensic investigations, particularly those involving homicides and unwitnessed deaths. However, traditional methods occasionally yield inconsistent estimates. Histological and molecular techniques are considered crucial in forensic pathology and are frequently employed to estimate the time interval of death. The gingiva is an oral mucosal tissue used to estimate PMI. This review aimed to examine the potential of histological methods to determine PMI using oral mucosal tissue, namely the gingiva, and to investigate changes that occur in oral mucosal tissue at different time intervals when compared with those in normal tissues. The oral mucosa comprises layers of stratified squamous epithelium and connective tissue. Similar to other body tissues, changes are known to occur in the gingiva after death, and these cellular and tissue changes should also be considered. Alterations in the gingiva include homogenisation, karyorrhexis, pyknosis, karyolysis, chromatin clumping, eosinophilia, collagen fibre degradation, and the loss of tissue architecture. Reviews collating the results of original trials have consistently reported how the oral mucosa is altered by autolysis and how such changes can be observed in histological tissue morphology after death. Histology is an acceptably accurate technique for estimating PMIs.

Effects of Non-Thermal Dielectric Barrier Discharge Plasma on Human Fibroblasts: A Narrative Review

Objectives: Fibroblasts are among the most critical connective tissue cells in almost all tissues and organs. Enhancement of fibroblast differentiation, proliferation, and morphogenesis is of paramount importance in tissue regeneration and wound healing. The non-thermal dielectric barrier discharge (DBD) plasma technology has recently gained interest due to its extensive applications and multiple biological effects. This review article outlines the applications of DBD plasma in dentistry, and its biological effects on human fibroblasts. Materials and Methods: Relevant keywords were searched in PubMed, Ovid, and Google Scholar online databases. The search strategy resulted in selection of 7 studies according to the eligibility criteria. Results: Most studies reported increased cell proliferation and viability after the application of DBD plasma. Four studies that focused on the development of adhesion-related appendages examined the morphology of fibroblast cells, including the creation of vinculin, protrusion, and actin cytoskeleton. Expression of cyclin D1/P27 genes and genes associated with adhesion and cell attachments was also reported in two studies. Conclusion: This narrative review discussed the effects of DBD plasma technology on proliferation and behavior of human fibroblasts, and reviewed the available articles in this regard. More in vivo studies are required to understand the exact effects of this emerging technology on human mesenchymal tissues.

Exosomal miR-17-5p derived from epithelial cells is involved in aberrant epithelium-fibroblast crosstalk and induces the development of oral submucosal fibrosis

Oral submucous fibrosis (OSF) is a chronic and inflammatory mucosal disease caused by betel quid chewing, which belongs to oral potentially malignant disorders. Abnormal fibroblast differentiation leading to disordered collagen metabolism is the core process underlying OSF development. The epithelium, which is the first line of defense against the external environment, can convert external signals into pathological signals and participate in the remodeling of the fibrotic microenvironment. However, the specific mechanisms by which the epithelium drives fibroblast differentiation remain unclear. In this study, we found that Arecoline-exposed epithelium communicated with the fibrotic microenvironment by secreting exosomes. MiR-17-5p was encapsulated in epithelial cell-derived exosomes and absorbed by fibroblasts, where it promoted cell secretion, contraction, migration and fibrogenic marker (α-SMA and collagen type I) expression. The underlying molecular mechanism involved miR-17-5p targeting Smad7 and suppressing the degradation of TGF-β receptor 1 (TGFBR1) through the E3 ubiquitination ligase WWP1, thus facilitating downstream TGF-β pathway signaling. Treatment of fibroblasts with an inhibitor of miR-17-5p reversed the contraction and migration phenotypes induced by epithelial-derived exosomes. Exosomal miR-17-5p was confirmed to function as a key regulator of the phenotypic transformation of fibroblasts. In conclusion, we demonstrated that Arecoline triggers aberrant epithelium-fibroblast crosstalk and identified that epithelial cell-derived miR-17-5p mediates fibroblast differentiation through the classical TGF-β fibrotic pathway, which provided a new perspective and strategy for the diagnosis and treatment of OSF.

The features of the reparative regeneration of an oral mucosa wound created under the exposure of a laser at a wavelength of 445 nm (a pilot study)

In clinical practice, an innovative laser technology that provides contactless preparation of soft tissues with a wavelength of 445 nm has been introduced. This study aimed to investigate the morphological changes in the oral mucosa when exposed to laser radiation at a wavelength of 445 nm in the ablation mode.An experimental study was conducted to analyze the dynamics of reparative regeneration in the wound caused by that particular type of radiation, utilizing the procedure of lower lip frenuloplasty as an illustration. 48 sexually mature male laboratory rats were chosen as the research object. The procedure of preparing the oral vestibule was executed by employing a contactless laser beam with a wavelength of 445 nm and a power of 0.7 W in continuous mode (CW) and an uninitiated fiber.Histological examination showed that 25 min after the surgery, there were large areas of coagulation necrosis in the oral mucosa in the area affected by the blue laser. In 48 h, the area of necrosis decreased both in size and depth. By the 7th day after the surgery, the necrotic masses had grown into the connective tissue, while marginal regeneration of the epithelium was noted. By the 14th day, the wound surface was completely epithelialized, represented by fibrous scar tissue. Clinically, around the mandibular incisors, there was a wide area of attached keratinized gingiva.The findings of histological examination indicate a necrosis of coagulation type in the region of tissue ablation and also show the absence of phase II of the inflammatory response (the stage of exudation), which expedites the process of epithelialization of the oral mucosa wound.

Topical Adipose Mesenchymal Stem cell metabolites regulate the expression of MMP-1, MMP-9, EGF, TGF-β in oral mucosa ulcer rat model

Objective

Matrix metalloproteinase (MMP-1 and -9), Epidermal Growth Factor (EGF), and Transforming Growth factor (TGF)-β are expressed in the oral ulcer wound-healing process. The Adipose mesenchymal stem cell metabolites (AdMSCMs) may accelerate wound-healing. This study aimed to investigate the expression of MMP-1, MMP-9, EGF, and TGF-β in the oral mucosa ulcer rat model treated with topical AdMSCMs.

Materials and Methods

Oral ulcer models were created in twenty healthy male Wistar rats (Rattus novergicus) divided into AdMSCMs and control groups. The oral ulcer model was treated topically using AdMSCMs oral gel three times daily for 3 and 7 days. The expression of MMP-1, MMP-9, EGF, TGF-β was evaluated through histological examination using the immunohistochemistry method. Independent t-test was used to compare the mean of expression of MMP-1, MMP-9, EGF, TGF-β between control and treatment groups (AdMSCMs), and paired t-test was used to analyze the mean between day 3 and day 7 of each group.

Results

A lower expression of MMP-1, MMP-9 in AdMSCMs group and higher expression EGF and TGF-β in AdMSCMs group compared to the control group in day 3 and day 7. Independent t-test results showed a significant difference in the expression of MMP-1, MMP-9, EGF between the control and AdMSCMs group in day 3 and day 7. Only TGF-β expression mean difference between day 3 and day 7 showed a significant difference compared to the control groups (p < 0.05).

Conclusions

AdMSCMs oral gel may accelerate oral ulcer healing models by reducing the expression MMP-1, MMP-9, and increasing EGF and TGF-β expressions during the wound-healing process.

Early feeding after free flap reconstruction of the oral cavity: A systematic review and meta-analysis

BACKGROUND

Traditionally, patients undergoing free flap reconstruction for oral cavity defects have been given nothing by mouth for 6-14 days post-operatively due to concern for orocutaneous fistula development.

METHODS

Multiple databases were screened for studies assessing the rate of orocutaneous fistula formation in early (≤5 days) versus late (>5 days) feeding groups following oral cavity free flap reconstruction. Fixed- and random-effects meta-analyses were used.

RESULTS

One randomized controlled trial, one prospective cohort, and three retrospective cohort studies were included. The early feeding group displayed no significant increase in orocutaneous fistula formation (RD = -0.02, p = 0.06) or free flap failure (RD = -0.01, p = 0.39), with a significantly shorter hospital length of stay (mean difference [days] = -2.43, p < 0.01).

CONCLUSIONS

While further prospective trials are necessary, initiation of oral intake before post-operative day 5 may be appropriate in properly selected patients following oral reconstruction.

Precise healing of oral and maxillofacial wounds: tissue engineering strategies and their associated mechanisms

Precise healing of wounds in the oral and maxillofacial regions is usually achieved by targeting the entire healing process. The rich blood circulation in the oral and maxillofacial regions promotes the rapid healing of wounds through the action of various growth factors. Correspondingly, their tissue engineering can aid in preventing wound infections, accelerate angiogenesis, and enhance the proliferation and migration of tissue cells during wound healing. Recent years, have witnessed an increase in the number of researchers focusing on tissue engineering, particularly for precise wound healing. In this context, hydrogels, which possess a soft viscoelastic nature and demonstrate exceptional biocompatibility and biodegradability, have emerged as the current research hotspot. Additionally, nanofibers, films, and foam sponges have been explored as some of the most viable materials for wound healing, with noted advantages and drawbacks. Accordingly, future research is highly likely to explore the application of these materials harboring enhanced mechanical properties, reduced susceptibility to external mechanical disturbances, and commendable water absorption and non-expansion attributes, for superior wound healing.

The Development of a Measuring System for Intraoral SpO2

Blood oxygen saturation (SpO2) is an essential indicator of a patient's general condition. However, conventional measurement methods have some issues such as time delay and interference by ambient light. Improved measurement methods must be developed, and there are no reports on intraoral measurements of SpO2 using wearable devices. Therefore, we aimed to establish an intraoral SpO2 measurement method for the first time. Twelve healthy adults participated in this study. The following steps were taken: (1) to identify the optimal measurement location, mid-perfusion index (PI) values were measured at six places on the mucosa of the maxilla, (2) to validate the optimal measurement pressure, PI values were obtained at different pressures, and (3) using the proposed mouthpiece device, SpO2 values in the oral cavity and on the finger were analyzed during breath-holding. The highest PI values were observed in the palatal gingiva of the maxillary canine teeth, with high PI values at pressures ranging from 0.3 to 0.8 N. In addition, changes in SpO2 were detected approximately 7 s faster in the oral cavity than those on the finger, which is attributed to their proximity to the heart. This study demonstrates the advantage of the oral cavity for acquiring biological information using a novel device.

Abbe Flap Division Before Two Weeks' Time: Harmful or Advantageous?

INTRODUCTION

The Abbe flap is a standard intervention to treat upper lip deformities in patients with bilateral cleft lip. This two-stage procedure requires a 2 to 3-week period in which the superior and inferior lips remain connected. This study evaluates the safety of Abbe flap division and inset prior to 14 days' time.

MATERIALS AND METHODS

A single institution, 8-year review of all patients with a bilateral cleft lip who underwent Abbe flap reconstruction was performed. Patients were classified into two groups: those whom division was performed 14 days or later and those with division earlier than 14 days.

RESULTS

A total of 26 patients were identified. Patients who underwent Abbe flap division in less than 14 days (n = 10) demonstrated an average time to division of 9.7 days (range 7-13 days) with no evidence of flap loss, wound breakdown or infection. Patients who underwent Abbe flap division within 14 days or more (n = 16) demonstrated an average time to division of 15 days with four minor complications and no flap loss.

CONCLUSION

Dividing the Abbe flap after the first postoperative week appears to be safe and without additional risk to flap loss or wound breakdown. A shorter time to Abbe flap division may decrease the burden of care on patients and their caregivers.

The impact of saliva collection methods on measured salivary biomarker levels

Saliva diagnostics have become increasingly popular due to their non-invasive nature and patient-friendly collection process. Various collection methods are available, yet these are not always well standardized for either quantitative or qualitative analysis. In line, the objective of this study was to evaluate if measured levels of various biomarkers in the saliva of healthy individuals were affected by three distinct saliva collection methods: 1) unstimulated saliva, 2) chew stimulated saliva, and 3) oral rinse. Saliva samples from 30 healthy individuals were obtained by the three collection methods. Then, the levels of various salivary biomarkers such as proteins and ions were determined. It was found that levels of various biomarkers obtained from unstimulated saliva were comparable to those in chew stimulated saliva. The levels of potassium, sodium, and amylase activity differed significantly among the three collection methods. Levels of all biomarkers measured using the oral rinse method significantly differed from those obtained from unstimulated and chew-stimulated saliva. In conclusion, both unstimulated and chew-stimulated saliva provided comparable levels for a diverse group of biomarkers. However, the results obtained from the oral rinse method significantly differed from those of unstimulated and chew-stimulated saliva, due to the diluted nature of the saliva extract.

A Thermally Stable Recombinant Human Fibronectin Peptide-Fused Protein (rhFN3C) for Faster Aphthous Ulcer (AU) Healing

Approximately 59.4-100% of head and neck cancer patients receiving radiotherapy or radio chemotherapy suffer from aphthous ulcers (AUs), which seriously affect the subsequent treatment. At the same time, AUs are a common oral mucosal disease with a high incidence rate among the population, often accompanied by severe pain, and affect both physical and mental health. Strategies to increase the ulcer healing rate and relieve pain symptoms quickly is a long-term clinical objective. Oral mucosal discontinuity is the main histological hallmark of AUs. So, covering the inner mucosal defect with an in vitro engineered oral mucosal equivalent shows good prospects for AU alleviation. Fibronectin (FN) is a glycopeptide in the extracellular matrix and exhibits opsonic properties, aiding the phagocytosis and clearance of foreign pathogens through all stages of ulcer healing. But native FN comes from animal blood, which has potential health risks. rhFN3C was designed with multi-domains of native FN, whose core functions are the recruitment of cells and growth factors to accelerate AU healing. rhFN3C is a peptide-fused recombinant protein. The peptides are derived from the positions of 1444-1545 (FNIII10) and 1632-1901 (FNIII12-14) in human native FN. We optimized the fermentation conditions of rhFN3C in E. coli BL21 to enable high expression levels. rhFN3C is thermally stable and nontoxic for L929, strongly promotes the migration and adhesion of HaCaT, decreases the incidence of wound infection, and shortens the mean healing time by about 2 days compared to others (p < 0.01). rhFN3C may have great potential for use in the treatment of AUs. The specific methods and mechanisms of rhFN3C are yet to be investigated.

Differential molecular profiles and associated functionalities characterize connective tissue grafts obtained at different locations and depths in the human palate

The present study aimed to assess the molecular profiles of subepithelial connective tissue grafts (CTGs) obtained at different locations and depths in the human palate. Sixty-four CTGs belonging to anterior deep (AD), anterior superficial (AS), posterior deep (PD), and posterior superficial (PS) groups were subjected to RNA-Sequencing and their transcriptomes were analyzed computationally. Functional correlations characterizing the CTG groups were validated by cell biological experiments using primary human palatal fibroblasts (HPFs) extracted from the CTGs. A clearly more pronounced location-dependent than depth-dependent difference between the grafts, with a minimal number of genes (4) showing no dependence on the location, was revealed. Epithelial, endothelial, and monocytic cell migration was strongly (P < 0.001) potentiated by AD- and PS-HPFs. Moreover, significantly increased expression of genes encoding C-C and C-X-C motif chemokine ligands as well as significantly (P < 0.01) activated p38 signaling suggested immunomodulatory phenotype for AD- and PS-HPFs. Increased growth factor gene expression and significantly activated (P < 0.001) Erk and Akt signaling in HPFs originating from A-CTGs implied their involvement in cell survival, proliferation, and motility. Prominent collagen-rich expression profile contributing to high mechanical stability, increased osteogenesis-related gene expression, and strongly activated (P < 0.001) Smad1/5/8 signaling characterized HPFs originating from P-CTGs. The present data indicate that in humans, differences between palatal CTGs harvested from different locations and depths appear to be location- rather than depth-dependent. Our findings provide the basis for future personalization of the therapeutic strategy by selecting an optimal graft type depending on the clinical indications.

Oral administration of Bifidobacterium breve improves anti-angiogenic drugs-derived oral mucosal wound healing impairment via upregulation of interleukin-10

Recent studies have suggested that long-term application of anti-angiogenic drugs may impair oral mucosal wound healing. This study investigated the effect of sunitinib on oral mucosal healing impairment in mice and the therapeutic potential of Bifidobacterium breve (B. breve). A mouse hard palate mucosal defect model was used to investigate the influence of sunitinib and/or zoledronate on wound healing. The volume and density of the bone under the mucosal defect were assessed by micro-computed tomography (micro-CT). Inflammatory factors were detected by protein microarray analysis and enzyme-linked immunosorbent assay (ELISA). The senescence and biological functions were tested in oral mucosal stem cells (OMSCs) treated with sunitinib. Ligated loop experiments were used to investigate the effect of oral B. breve. Neutralizing antibody for interleukin-10 (IL-10) was used to prove the critical role of IL-10 in the pro-healing process derived from B. breve. Results showed that sunitinib caused oral mucosal wound healing impairment in mice. In vitro, sunitinib induced cellular senescence in OMSCs and affected biological functions such as proliferation, migration, and differentiation. Oral administration of B. breve reduced oral mucosal inflammation and promoted wound healing via intestinal dendritic cells (DCs)-derived IL-10. IL-10 reversed cellular senescence caused by sunitinib in OMSCs, and IL-10 neutralizing antibody blocked the ameliorative effect of B. breve on oral mucosal wound healing under sunitinib treatment conditions. In conclusion, sunitinib induces cellular senescence in OMSCs and causes oral mucosal wound healing impairment and oral administration of B. breve could improve wound healing impairment via intestinal DCs-derived IL-10.

Histological characterization of the human masticatory oral mucosa. A histochemical and immunohistochemical study

BACKGROUND

Histology of human oral mucosa is closely related with its function and anatomical location, and a proper characterization of the human masticatory oral mucosa could be very useful in periodontal pathology.

OBJECTIVE

In the present work, we have carried out a comprehensive study in order to determine the main histological features of parakeratinized (POM) and orthokeratinized (OOM) masticatory human oral mucosa using light and electron microscopy.

METHODS

To perform this, we have used several histological, histochemical and immunohistochemical methods to detect key markets at the epithelial, basement membrane and connective tissue levels.

RESULTS

Our results demonstrated that POM and OOM share many histological similarities, as expected. However, important differences were observed at the epithelial layer of POM, that was significantly thicker than the epithelial layer found in OOM, especially due to a higher number of cells at the stratum spinosum. The expression pattern of CK10 and filaggrin revealed intense signal expression in OOM as compared to POM. Collagen and proteoglycans were more abundant in OOM stroma than in POM. No differences were found for blood vessels and basement membrane.

CONCLUSION

These results may contribute to a better understanding of the pathological conditions affecting the human masticatory oral mucosa. In addition, these findings could be useful for the generation of different types of oral mucosa by tissue engineering techniques.

RESEARCH HIGHLIGHTS

Microscopical features of parakeratinized and orthokeratinized masticatory human oral mucosa showed important differences at both, epithelial and stromal levels. Parakeratinized masticatory human oral mucosa exert thicker epithelial layer, especially, at the stratum spinosum in comparison to orthokeratinized human oral mucosa. Cytokeratin 10 and filaggrin human epithelial markers were intensively expressed in orthokeratinized masticatory human oral mucosa in comparison to parakeratinized masticatory human oral mucosa. At the stromal level, orthokeratinized masticatory human oral mucosa exhibit higher levels of collagen and proteoglycans than parakeratinized masticatory oral mucosa. The deep knowledge of histological features of masticatory oral mucosa could lead to a better understanding of oral mucosa pathology and advanced treatments.

Characterization of red algae (Gracilaria verrucosa) on potential application for topical treatment of oral mucosa wounds in Rattus norvegicus

Wound healing in the mouth has its challenges due to masticatory movements and the presence of bacteria that can inhibit its process. The aim of this study was to analyze the contents of red algae (Gracilaria verrucosa) from Indonesia, and its potential as a wound-healing agent for oral wounds using animal model. Red algae content was determined by phytochemical tests and gas chromatography-mass spectroscopy (GC-MS). The wound was made by making an incision on the gingival mucosa of Rattus norvegicus and the parameters assessed were bleeding time, number of fibroblast cells, and time of wound closure. Three doses of G. verrucosa gel were used (2.5%, 5%, and 10%) and the gels were applied twice a day, at 6:00 and 18:00. Application was carried out topically by applying 0.1 ml of gel to the incision wound using a 1 mL syringe. Our phytochemical test indicated that the G. verrucosa contained alkaloids, steroids, flavonoids, and phenols. The dominant contains of the G. verrucosa were glycerol (36.81%), hexadecenoic acid (20.74%), and cholesterol (7.4%). The hemostasis test showed that the 2.5% G. verrucosa extract gel had the shortest bleeding time, 33.98±2.66 seconds. On the seventh day of the initial proliferation phase, the number of fibroblasts was not significantly different among groups. On day 14, the number of fibroblasts was only significantly different between 10% G. verrucosa and untreated group (p=0.007). On day 28, however, both 5% and 10% G. verrucosa were significantly higher compared to untreated group, both had p=0.010. Daily clinical examination showed that animals that were given 2.5% and 5% of G. verrucosa extract gel experienced wound closure on day 10. Animals treated with 10% of extract gel, all wounds healed on day 9. This study suggested that G. verrucosa extract could accelerate wound closure and wound healing.

Accelerated Oral Healing by Angelica gigas Nakai from Hot Melt Extrusion Technology: An In Vitro Study

Background and Objectives: In spite of the oral environment being healing-prone, its dynamic changes may affect wound healing. The purpose of this study was to assess the oral wound healing effect of Angelica gigas Nakai (AG) prepared by hot-melt extrusion. Materials and Methods: Human gingival fibroblast (HGF) cells were treated with AG or AG via hot-melt extrusion (AGH) for 24 h to determine the optimal concentration. For evaluating the anti-inflammatory effect of AG and AGH, a nitric oxide assay was performed under lipopolysaccharide (LPS) stimulation. The wound-healing effects of AG and AGH were evaluated using cell proliferation/migration assays and wound-healing marker expression through qRT-PCR. Results: Both AG and AGH showed no cytotoxicity on HGH cells. Regarding nitric oxide production, AGH significantly decreased LPS-induced nitric oxide production (p < 0.05). AGH showed a significantly positive result in the cell proliferation/cell migration assay compared with that in AG and the control. Regarding wound healing marker expression, AGH showed significantly greater VEGF and COL1α1 expression levels than those in the others (p < 0.05), whereas α-SMA expression was significantly different among the groups. Conclusions: Within the limits of this study, AGH accelerated oral wound healing in vitro.

Acute normal tissue responses in a murine model following fractionated irradiation of the head and neck with protons or X-rays

BACKGROUND

The purpose of this study was to investigate acute normal tissue responses in the head and neck region following proton- or X-irradiation of a murine model.

MATERIALS AND METHODS

Female C57BL/6J mice were irradiated with protons (25 or 60 MeV) or X-rays (100 kV). The radiation field covered the oral cavity and the major salivary glands. For protons, two different treatment plans were used, either with the Bragg Peak in the middle of the mouse (BP) or outside the mouse (transmission mode; TM). Delivered physical doses were 41, 45, and 65 Gy given in 6, 7, and 10 fractions for BP, TM, and X-rays, respectively. Alanine dosimetry was used to assess delivered doses. Oral mucositis and dermatitis were scored using CTC v.2.0-based tables. Saliva was collected at baseline, right after end of irradiation, and at day 35.

RESULTS

The measured dose distribution for protons (TM) and X-rays was very similar. Oral mucositis appeared earlier, had a higher score and was found in a higher percentage of mice after proton irradiation compared to X-irradiation. Dermatitis, on the other hand, had a similar appearance after protons and X-rays. Compared to controls, saliva production was lower right after termination of proton- and X-irradiation. The BP group demonstrated saliva recovery compared to the TM and X-ray group at day 35.

CONCLUSION

With lower delivered doses, proton irradiation resulted in similar skin reactions and increased oral mucositis compared to X-irradiation. This indicates that the relative biological effectiveness of protons for acute tissue responses in the mouse head and neck is greater than the clinical standard of 1.1. Thus, there is a need for further investigations of the biological effect of protons in normal tissues.

Can an Alginate-based Wound Dressing Modified with Garden Cress Substitute for COE-PAK as a Wound Dressing? An In Vitro Study

AIM

The aim of the current study was to prepare a natural oral wound dressing from alginate modified with garden cress (GC), a rich source of antibacterial phytochemical compounds essential for wound healing.

MATERIALS AND METHODS

Sodium alginate (SA) dressing (negative control group), was prepared and modified with GC seeds extracts (25 µg/mL and 50 µg/mL) as the intervention groups, and COE-PAK was the positive control group. Cytotoxicity was measured using WST-1 assay (n = 15) after 24 and 48 hours. The in vitro wound healing assay (n = 15) was assessed in terms of wound width, and cell migration rate (0, 24, 48, and 72 hours). Agar diffusion test was performed to investigate the antibacterial action (n = 15) of the groups against Streptococcus mutans and Lactobacillus casei strains. Results were significant at p ≤ 0.05.

RESULTS

There was no statistically significant difference in cytotoxicity in all groups (p = 0.24 at 24 hours and 0.1 at 48 hours). Garden cress-containing groups revealed the lowest mean value of wound width (0.27 mm ± 0.01 and 0.23 mm ± 0.01 for 25 µg/mL and 50 µg/mL, respectively at 48 hours) and the highest mean value of cell migration rate (0.013 mm/hour ± 0.004 and 0.014 mm/hour ± 0.004 for 25 µg/mL and 50 µg/mL, respectively at 48 hours), in addition to the highest antibacterial action (1.49 mm ± 0.05 and 2.14 mm ± 0.09 for 25 µg/mL and 50 µg/mL, respectively against S. mutans, 1.43 mm ± 0.07 and 2.55 mm ± 0.09 for 25 µg/mL and 50 µg/mL, respectively against L. casei).

CONCLUSION

Alginate wound dressing modified with GC extract could be considered a promising wound dressing material in terms of wound healing and antibacterial action.

CLINICAL SIGNIFICANCE

Ready-to-use alginate-based wound dressing modified with GC extract may represent a promising natural alternative to the most commonly used oral wound dressing (COE-PAK).

Functional drug-delivery hydrogels for oral and maxillofacial wound healing

The repair process for oral and maxillofacial injuries involves hemostasis, inflammation, proliferation, and remodeling. Injury repair involves a variety of cells, including platelets, immune cells, fibroblasts, and various cytokines. Rapid and adequate healing of oral and maxillofacial trauma is a major concern to patients. Functional drug-delivery hydrogels play an active role in promoting wound healing and have shown unique advantages in wound dressings. Functional hydrogels promote wound healing through their adhesive, anti-inflammatory, antioxidant, antibacterial, hemostatic, angiogenic, and re-epithelialization-promoting properties, effectively sealing wounds and reducing inflammation. In addition, functional hydrogels can respond to changes in temperature, light, magnetic fields, pH, and reactive oxygen species to release drugs, enabling precise treatment. Furthermore, hydrogels can deliver various cargos that promote healing, including nucleic acids, cytokines, small-molecule drugs, stem cells, exosomes, and nanomaterials. Therefore, functional drug-delivery hydrogels have a positive impact on the healing of oral and maxillofacial injuries. This review describes the oral mucosal structure and healing process and summarizes the currently available responsive hydrogels used to promote wound healing.

Novel Strategies for Orofacial Soft Tissue Regeneration

Significance: Orofacial structures are indispensable for speech and eating, and impairment disrupts whole-body health through malnutrition and poor quality of life. However, due to the unique and highly specialized cell populations, tissue architecture, and healing microenvironments, regeneration in this region is challenging and inadequately addressed to date. Recent Advances: With increasing understanding of the nuanced physiology and cellular responses of orofacial soft tissue, novel scaffolds, seeded cells, and bioactive molecules were developed in the past 5 years to specifically target orofacial soft tissue regeneration, particularly for tissues primarily found within the orofacial region such as oral mucosa, taste buds, salivary glands, and masseter muscles. Critical Issues: Due to the tightly packed and complex anatomy, orofacial soft tissue injury commonly implicates multiple tissue types, and thus functional unit reconstruction in the orofacial region is more important than single tissue regeneration. Future Directions: This article reviews the up-to-date knowledge in this highly translational topic, which provides insights into novel biologically inspired and engineered strategies for regenerating orofacial component tissues and functional units.

Clinical Signs of Kawasaki Disease from the Perspective of Epithelial-to-Mesenchymal Transition Recruiting Erythrocytes: A Literature Review

Kawasaki disease (KD) is a systemic vasculitis affecting children younger than 5 years of age. Early period in life is marked by rapid somatic growth with cell proliferation and immaturity of the immunity with dominant innate immune system. Coronary complications in KD are the most common acquired heart disease in children, yet the diagnosis of KD still depends on the clinical diagnostic criteria. Glossy red lips and conjunctival injection are characteristic signs enabling pediatricians to make the initial diagnosis of KD; however, little is known why these are so characteristic. The diagnostic criteria of KD seem to be scattered in seemingly irrelevant body systems such as the eyes, lips, skin, and heart. KD is classified as a connective tissue disease. Recently, red blood cells (RBCs) have emerged as important modulators in innate immune response. RBCs are reported to participate in extracellular matrix remodeling and upregulating matrix metalloproteinase (MMP) expression in dermal fibroblasts. Also, fibroblast growth factors and microRNAs associated with fibrosis are drawing attention in KD. The cardinal signs of KD appear at the border of muco-cutaneous junction. Head and neck regions are abundant in tissues undergoing epithelial-to-mesenchymal transition (EMT). Interstitial carditis and valve insufficiency as well as coronary arterial lesions may complicate KD, and these lesions present in tissues that originated from epicardial progenitor cells by EMT. Having reviewed the recent research on KD, we presume that the signs of KD present at borders between keratinized and non-keratinized stratified squamous epithelium where the EMT is still ongoing for the rapid somatic growth where RBCs are recruited as an innate immune response and to prevent excessive fibrosis in mucosa. KD presents scarcely in adults with somatic growth and immune maturation completed. In this review, we attempted to explain the reasons for the clinical manifestations of KD and to search for a link among the diagnostic clues in the perspective of EMT during the somatic growth and immune system maturation in children with KD.

In Vitro Cell Proliferation and Migration Properties of Oral Mucosal Fibroblasts: A Comparative Study on the Effects of Cord Blood- and Peripheral Blood-Platelet Lysate

Cord blood-platelet lysate (CB-PL), containing growth factors such as a platelet-derived growth factor, has a similar efficacy to peripheral blood-platelet lysate (PB-PL) in initiating cell growth and differentiation, which makes it a unique alternative to be implemented into oral ulceration healing. This research study aimed to compare the effectiveness of CB-PL and PB-PL in promoting oral wound closure in vitro. Alamar blue assay was used to determine the optimal concentration of CB-PL and PB-PL in enhancing the proliferation of human oral mucosal fibroblasts (HOMF). The percentage of wound closure was measured using the wound-healing assay for CB-PL and PB-PL at the optimal concentration of 1.25% and 0.3125%, respectively. The gene expressions of cell phenotypic makers (Col. I, Col. III, elastin and fibronectin) were determined via qRT-PCR. The concentrations of PDGF-BB were quantified using ELISA. We found that CB-PL was as effective as PB-PL in promoting wound-healing and both PL were more effective compared to the control (CTRL) group in accelerating the cell migration in the wound-healing assay. The gene expressions of Col. III and fibronectin were significantly higher in PB-PL compared to CB-PL. The PDGF-BB concentration of PB-PL was the highest and it decreased after the wound closed on day 3. Therefore, we concluded that PL from both sources can be a beneficial treatment for wound-healing, but PB-PL showed the most promising wound-healing properties in this study.

Cytokines secreted by inflamed oral mucosa: implications for oral cancer progression

The oral mucosa has an essential role in protecting against physical, microbial, and chemical harm. Compromise of this barrier triggers a wound healing response. Key events in this response such as immune infiltration, re-epithelialization, and stroma remodeling are coordinated by cytokines that promote cellular migration, invasion, and proliferation. Cytokine-mediated cellular invasion and migration are also essential features in cancer dissemination. Therefore, exploration of cytokines that regulate each stage of oral wound healing will provide insights about cytokines that are exploited by oral squamous cell carcinoma (SCC) to promote tumor development and progression. This will aid in identifying potential therapeutic targets to constrain SCC recurrence and increase patient survival. In this review, we discuss cytokines that overlap in oral wounds and SCC, emphasizing how these cytokines promote cancer progression.

Single-cell transcriptomic analysis of oral masticatory and lining mucosa-derived mesenchymal stromal cells

AIM

To reveal the heterogeneity of ex vivo-cultured human mesenchymal stromal cells derived from either masticatory or lining oral mucosa.

MATERIALS AND METHODS

Cells were retrieved from the lamina propria of the hard palate and alveolar mucosa of three individuals. The analysis of transcriptomic-level differences was accomplished using single-cell RNA sequencing.

RESULTS

Cluster analysis clearly distinguished between cells from the masticatory and lining oral mucosa, and revealed 11 distinct cell sub-populations, annotated as fibroblasts, smooth muscle cells or mesenchymal stem cells. Interestingly, cells presenting a mesenchymal stem cell-like gene expression pattern were predominantly found in masticatory mucosa. Although cells of masticatory mucosa origin were highly enriched for biological processes associated with wound healing, those from the lining oral mucosa were highly enriched for biological processes associated with the regulation of epithelial cells.

CONCLUSIONS

Our previous work had shown that cells from the lining and masticatory oral mucosae are phenotypically heterogeneous. Here, we extend these findings to show that these changes are not the result of differences in averages but rather represent two distinct cell populations, with mesenchymal stem cells more common in masticatory mucosa. These features may contribute to specific physiological functions and have relevance for potential therapeutic interventions.

Photo-crosslinked GelMA loaded with dental pulp stem cells and VEGF to repair critical-sized soft tissue defects in rats

BACKGROUND

Tissue engineering of skin and mucosa is essential for the esthetic and functional reconstruction of individuals disfigured by trauma, resection surgery, or severe burns while overcoming the limited amount of autograft and donor site morbidity.

PURPOSE

We aimed to determine whether a combination of Gelatin-methacryloyl (GelMA) hydrogel scaffold alone or loaded with either dental pulp stem cells (DPSCs) and/or vascular endothelial growth factor (VEGF) could improve skin wound healing in rats.

MATERIALS AND METHODS

Four 10 mm full-thickness skin defects were created on the dorsum of 15 Sprague-Dawley rats. The wounds were treated with GelMA alone, GelMA+DPSCs, or GelMA+DPSCs+VEGF. Unprotected wounds were used as controls. Animals were euthanized at 1-, 2-, and 4 weeks post-surgery, and the healing wounds were harvested for clinical, histological, and RT-PCR analysis.

RESULTS

No signs of clinical inflammation were observed among all groups. Few and sparse mononuclear inflammatory cells were observed in GelMA+DPSCs and GelMA+DPSCs+VEGF groups at 2 weeks, with complete epithelialization of the wounds. At 4 weeks, the epidermis in GelMA+DPSCs and GelMA+DPSCs+VEGF groups was indistinguishable from the empty defect and GelMA groups. The decrease in cellularity and increase in density of collagen fibers were observed over time in both GelMA+DPSCs and GelMA+DPSCs+VEGF groups but were more evident in the GelMA+DPSCs+VEGF group. The GelMA+DPSCs+VEGF group showed a higher expression of the KER 10 gene at all time points compared with the other groups. Expression of Col1 A1 and TGFβ-1 were not statistically different over time neither among the groups.

CONCLUSION

GelMA scaffolds loaded with DPSCs, and VEGF accelerated the re-epithelialization of skin wounds.

A deep learning algorithm for classification of oral lichen planus lesions from photographic images: A retrospective study

INTRODUCTION

Deep learning methods have recently been applied for the processing of medical images, and they have shown promise in a variety of applications. This study aimed to develop a deep learning approach for identifying oral lichen planus lesions using photographic images.

MATERIAL AND METHODS

Anonymous retrospective photographic images of buccal mucosa with 65 healthy and 72 oral lichen planus lesions were identified using the CranioCatch program (CranioCatch, Eskişehir, Turkey). All images were re-checked and verified by Oral Medicine and Maxillofacial Radiology experts. This data set was divided into training (n = 51; n = 58), verification (n = 7; n = 7), and test (n = 7; n = 7) sets for healthy mucosa and mucosa with the oral lichen planus lesion, respectively. In the study, an artificial intelligence model was developed using Google Inception V3 architecture implemented with Tensorflow, which is a deep learning approach.

RESULTS

AI deep learning model provided the classification of all test images for both healthy and diseased mucosa with a 100% success rate.

CONCLUSION

In the healthcare business, AI offers a wide range of uses and applications. The increased effort increased complexity of the job, and probable doctor fatigue may jeopardize diagnostic abilities and results. Artificial intelligence (AI) components in imaging equipment would lessen this effort and increase efficiency. They can also detect oral lesions and have access to more data than their human counterparts. Our preliminary findings show that deep learning has the potential to handle this significant challenge.

Phytohustil® and root extract of Althaea officinalis L. exert anti-inflammatory and anti-oxidative properties and improve the migratory capacity of endothelial cells in vitro

Introduction: Althaea officinalis L.'s root extract (REA) has been used as a medicinal plant since ancient times to treat a cough. Applying REA leads to a protective film that induces a faster regeneration of the lesioned laryngopharyngeal mucosa caused by dry coughs. The buccopharyngeal mucosa is a highly vascularized tissue. In this regard, anti-inflammatory/-oxidant phytochemicals that improve the repair of the lesion site, e.g., neovascularization in the wound, are critical for promoting healing. For this reason, it is essential to investigate the effects of Phytohustil^® and REA on different cellular components of the mucosa under conditions similar to those found in the injured mucosa. Thus, this in vitro study investigated the anti-inflammatory/oxidative and pro-migratory properties of Phytohustil^® cough syrup on vascular endothelial cells. Methods: Human umbilical vein endothelial cells (HUVEC) were pretreated (24 h) with Phytohustil^®, its excipients, or REA, followed by incubation with hydrogen peroxide (H₂O₂; 1 h; pro-oxidative) or with lipopolysaccharides (LPS; 3 h; pro-inflammatory). Viability and cytotoxicity were measured by PrestoBlue^® assay. Intracellular reactive oxygen species (ROS) were quantified with 20-70-dichlorofluorescein diacetate (DCFDA). The release of interleukin 6 (IL6) was determined by enzyme-linked immunosorbent assay (ELISA). The migratory capacity of HUVEC was measured using a scratch assay. Results: Our results show that Phytohustil^®, its excipients and REA were not cytotoxic. Pretreatment of HUVEC (24 h) with Phytohustil^® or REA inhibited the LPS-activated IL6 release. Phytohustil^® or REA inhibited the H₂O₂-induced cytotoxicity and intracellular ROS production. Phytohustil^® and REA significantly stimulated wound closure compared to the control. Conclusion: Our data show that Phytohustil^® and REA have anti-inflammatory/-oxidant properties and improve the migratory capacity of vascular endothelial cells. These properties may contribute to the healing characteristics of Phytohustil^® and support the benefit of Phytohustil^® in patient's treatment of irritated oral mucosa.

Type-2 epithelial-mesenchymal transition in oral mucosal nonneoplastic diseases

The oral mucosa is a membranous structure comprising epithelial and connective tissue that covers the oral cavity. The oral mucosa is the first immune barrier to protect the body against pathogens for systemic protection. It is frequently exposed to mechanical abrasion, chemical erosion, and pathogenic invasion, resulting in oral mucosal lesions, particularly inflammatory diseases. Epithelial-mesenchymal transition (EMT) is a crucial biological process in the pathogenesis of oral mucosal disorders, which are classified into three types (types 1, 2, and 3) based on their physiological consequences. Among these, type-2 EMT is crucial in wound repair, organ fibrosis, and tissue regeneration. It causes infectious and dis-infectious immunological diseases, such as oral lichen planus (OLP), oral leukoplakia, oral submucosal fibrosis, and other precancerous lesions. However, the mechanism and cognition between type-2 EMT and oral mucosal inflammatory disorders remain unknown. This review first provides a comprehensive evaluation of type-2 EMT in chronically inflammatory oral mucosal disorders. The aim is to lay a foundation for future research and suggest potential treatments.

Soft-Tissue Healing Assessment after Extraction and Socket Preservation Using Platelet-Rich Fibrin (PRF) in Smokers: A Single-Blinded, Randomized, Controlled Clinical Trial

Background: Wound healing is essential in any surgical procedure, and multiple factors, such as smoking, can impair it. The aim of this clinical trial was to evaluate the ability of platelet-rich fibrin to enhance socket wound healing in smokers. Methods: A total of 18 smoker participants with forty non-restorable upper molars indicated for extraction were recruited to the study and were randomly allocated to four different groups for the assessment of four techniques: advanced platelet-rich fibrin (A-PRF), factor-enriched bone graft matrix with advanced platelet-rich fibrin (A/S-PRF), freeze-dried bone allograft and crosslinked collagen membrane (FDBA/CM), and resorbable collagen plug (RCP). One examiner clinically measured soft-tissue closure and the healing pattern using a periodontal probe and a healing index. Each subject was given a questionnaire after each follow-up visit to record several patient-reported experience measures (PREMs). This was conducted at baseline and 10, 21, and 28 days after the extraction procedure. Results: Both A-PRF and A/S-PRF showed significant results in terms of mesio-distally (p = 0.012), and healing pattern parameters (p < 0.0001), while RCP showed the least favorable outcome. Conclusions: Different forms of PRF exhibited enhanced wound closure and healing patterns, as well as reduced post-operative complications among smokers.

Extracts of Rheum palmatum and Aloe vera Show Beneficial Properties for the Synergistic Improvement of Oral Wound Healing

Various local and systemic factors compromise oral wound healing and may lead to wound dehiscence, inflammation, or ulcers. Currently, there is a lack of topical therapeutical options. Thus, this study aimed to investigate the effect of Aloe vera (AV) and Rheum palmatum root (RPR) on oral wound healing capacity in vitro. The effect of AV and RPR on human primary fibroblast viability and migration was studied by measuring metabolic activity and gap closure in a scratch assay. Furthermore, cell cycle distribution and cytoskeletal features were analyzed. Antimicrobial activity against the oral pathogen Porphyromonas gingivalis was evaluated by broth microdilution assay. AV and RPR increased fibroblast migration after single agent treatment. Synergistic effects of the plant extract combination were observed regarding cellular migration which were confirmed by calculation of the phenomenological combination index (pCI), whereas the cell cycle distribution was not influenced. Furthermore, the combination of AV and RPR showed synergistic antibacterial effects as determined by the fractional inhibitory concentration index. This study demonstrated that the combination of AV and RPR can promote the migration of human primary fibroblasts in vitro and exert antimicrobial efficacy against P. gingivalis, suggesting these compounds for the topical treatment of wound healing disorders.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2021 dental literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to coverage of this broad topical area. Specific subject areas addressed, in order of the appearance in this report, include COVID-19 and the dental profession (new); prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence daily dental treatment decisions with an emphasis on future trends in dentistry. With the tremendous volume of dentistry and related literature being published daily, this review cannot possibly be comprehensive. Rather, its purpose is to update interested readers and provide important resource material for those interested in pursuing greater details on their own. It remains our intent to assist colleagues in negotiating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the patients and dental problems they encounter.

Impacts of Pesticides on Oral Cavity Health and Ecosystems: A Review

Pesticides are chemical substances used to control, prevent, or destroy agricultural, domestic, and livestock pests. These compounds produce adverse changes in health, and they have been associated with the development of multiple chronic diseases. This study aimed to present a detailed review of the effect of pesticides on the oral cavity and the oral microbiome. In the oral cavity, pesticides alter and/or modify tissues and the microbiome, thereby triggering imbalance in the ecosystem, generating an inflammatory response, and activating hydrolytic enzymes. In particular, the imbalance in the oral microbiome creates a dysbiosis that modifies the number, composition, and/or functions of the constituent microorganisms and the local response of the host. Pesticide exposure alters epithelial cells, and oral microbiota, and disrupts the homeostasis of the oral environment. The presence of pesticides in the oral cavity predisposes the appearance of pathologies such as caries, periodontal diseases, oral cancer, and odontogenic infections. In this study, we analyzed the effect of organochlorines, organophosphates, pyrethroids, carbamates, bipyridyls, and triazineson oral cavity health and ecosystems.